The next few months should be interesting. I'm really starting to like the way Google Plus (G+ now seems to be the preferred abbreviation) works - it's more flexible and powerful than Facebook, and has massive potential. The way Circles works makes sense and it allows me much more control over how I share and who with.
I haven't played around with nearly all the features yet, but as my circles begin to fill out I'm seeing how good the base design and concept is. Now the main issue - Facebook has captured the masses and most casual users have mastered the interface. Facebook crushed MySpace by being simple and approachable. But will the masses migrate yet again? People like me are already on G+ and more are coming all the time, but we're all "early adopters". Most of my Facebook friends do NOT fall into that category.
I suppose time will tell... Let me know if you want a G+ invite to try it out for yourself. Click here for my G+ page.